5th Gen rear pillar speakers?

Has anyone here ever installed speakers at or near ear level somewhere in the rear of the 4Runner? My 2011 FJ Cruiser has factory rear pillar speaker locations at ear level that just barely hold a 3.5" coaxial. Having something like that in the 4Runner at ear level I think might be a real plus instead of just blasting into the back of the back seat and across the vehicle at the bottom of the rear doors. A perforation job in the plastic is not a problem. They are almost invisible when done well. It seems like there ought to be room somewhere back there to mount a 3.5" or even something like this if a smaller size is needed: Celestion AN2775 2-3/4" Full-Range Compact Array DriverCelestion AN2775 2-3/4" Full-Range Compact Array Driver

 

Has anyone been inside these areas to see if there is any space for something like a midrange or even a 3.5" coaxial like the dashboard locations?